Device for continuous mixing of powdered materials

ABSTRACT

A device for continuous mixing of powdered materials which include ferro-magnetic components, has a drum mounted for rotation on its own axis and made in the form of a polyhedral truncated pyramid. The drum is disposed with the axis inclined to the horizontal and is fed at one end thereof with powdered materials which are to be thoroughly mixed, and the mixed materials are discharged at the other end. The inside of the drum is provided on its longitudinal edges with rigidly mounted baffles which are made of ferromagnetic material, and the baffles are arranged along a helix. A magnetic system which can generate a pulse magnetic field is stationarily mounted above the drum and parallel to a generatrix of the drum. The magnetic field reaches the inside of the drum through the ferromagnetic baffles which act as cores and aids a redistribution and thorough mixing of the ferromagnetic components with the rest of the components in the powdered material. In order to increase the effect of the pulse magnetic field by effectively increasing the proximity of the baffles to the magnetic system, additional ferromagnetic members may be securingly mounted on the outside of the drum to rotate therewith and arranged so as to nearly bridge a gap between the drum and the magnetic means, whereby the effect of the magnetic field inside the drum is increased.

atent 1 Shvartsman et al.

[ DEVICE FOR CONTINUOUS MIXING 0F POWDERED MATERIALS [76] Inventors: Valery Lvovich Shvartsman, ulitsa Kuibysheva 36, kv, 64, Donetsk; Anatoly Kirillovich Gaiduchenko, ulitsa Oktyabrskoi revoljutsii 19, kv. l6, Kiev, both of U.S.S.R.

[22] Filed: July 28, 1971 [21] App]. No.: 166,890

[52] US. Cl 259/3, 259/89, 259/DIG. 46 [51] Int. Cl. B01f 9/02, B0lf 13/08, BOlf 3/18 [58] Field of Search..... 259/3, 14, 30, 57, 81 R, 89, 259/DIG. 46

[56] References Cited UNITED STATES PATENTS 3,502,304 3/1970 Pfrengle 259/3 2,394,450 2/1946 Hogaboom 259/89 2,088,099 7/1937 Venable 259/3 X 2,774,803 12/1956 Dreyfus... 259/DIG. 46

Geer 259/89 [451 Jan. 22, 1974 [57] ABSTRACT A device for continuous mixing of powdered materials which include ferro-magnetic components, has a drum mounted for rotation on its own axis and made in the form of a polyhedral truncated pyramid. The drum is disposed with the axis inclined to the horizontal and is fed at one end thereof with powdered materials which are to be thoroughly mixed, and the mixed materials are discharged at the other end. The inside of the drum is provided on its longitudinal edges with rigidly mounted baffles which are made of ferromagnetic material, and the baffles are arranged along a helix. A magnetic system which can generate a pulse magnetic field is stationarily mounted above the drum and parallel to a generatrix of the drum. The magnetic field reaches the inside of the drum through the ferromagnetic baffles which act as cores and aids a redistribution and thorough mixing o'f the ferromagnetic components with the rest of the components in the powdered material. In order to increase the effect of the pulse magnetic field by effectively increasing the proximity of the baffles to the magnetic system, additional ferromagnetic members may be securingly mounted on the outside of the drum to rotate therewith and arranged so as to nearly bridge a gap between the drum and the magnetic means, whereby the effect of the magnetic field inside the drum is increased.

PATENTEI] JAN 2 2 I974 SHEEI 2 [IF 2 DEVICE FOR CONTINUOUS MIXDIG OF POWDERED MATERIALS BACKGROUND OF THE INVENTION The present invention relates to devices for continuous mixing of powdered materials and can find a wide application in:

powder metallurgy for preparation of mixtures in the production of iron powder, in averaging iron powder and in the manufacture of charge for producing ceramic metal pieces;

in ferrous metallurgy for preparing a charge for subsequent agglomeration and a mixture of iron ore concentrates with additions in the production of pellets; I 1

in welding practice for preparing core wire materials and in other fields of industry where there is a need for blending powdered materials containing at least.

40 percent of ferro-magnetic components.

DESCRIPTION OF PRIOR ART Known at present are batchand continuous-action devices for mixing powdered materials. One such known device includes mechanical mixers of the drumtype, comprising a revolving drum. Fastened to the drum interior by means of a rigid joint are baffle plates displaced relative to each other and overlapping par tially a drum cavity in the cross section.

As for the baffle plates, use may be made of sloping spiral deflectors, longitudinal racks and a number of other auxiliary arrangements, whose function is to intensify the degree of mixing.

When the above type mixers are used for blending pulverized materials differing strongly in specific weights, the mixing process requires a longer mixing time. The long mixing duration required may be attributed to the fact that as the drum is rotating there is no positive force, which would'act upon the particles, de termining or influencing the curvilinear path of their motion, the components in the mixture are transferred only by gravity. The baffle plates or deflectors arranged within the drum provide the requisite conditions for swirling the stream of materials, this, however, does not lead to asubstantial increase in the effectiveness and circulation rate of the components being mixed.

In the mean time when the drum rotates for a long time the comparatively light-weight particles tend to float up into upper layers which adversely effects the homogeneity of the mixture.

Known also are other apparatus using the foregoing devices for performing continuous mixing of powdered materials, though they havenot proved successful due to the above reasons.

There are also known mixing apparatus with stationary drums enclosing a two-shaft arrangement with rotating blades. Such apparatus ensure a positive mixing of the particles but nevertheless the process rate is not so high to perform it continuously in the apparatus of the above type. i

SUMMARY OF THE INVENTION The present invention is, in essence, aimed at developing a device for continuous mixing of powdered material, which would ensure a higher production rate by using the continuous mixing process. Another object of the present invention is to provide a device for the con tinuous mixing of powdered materials, which device would assure a high degree of homogeneity of a mixture along with high intensity of the process, achieved through the use of magnetic properties of ferromagnetic components of the materials, being mixed.

According to the specified and other objects of this invention, a device for continuous mixing of powdered materials, comprises a revolving drum having its inside fitted with baffle plates fastened to it by means of rigid joints, the plates being displaced with regard to each other and overlapping partially the drum cavity in a cross-section; and according to the invention, the revolving drum is a polyhedral truncated pyramid with a stationary magnetic system mounted above and generating a pulse magnetic field influencing the baffle plates which are made in the form of ferro-magnetic cores. The ferromagnetic components of the powdered materials get influenced by the magnetic field through the medium of the baffle plates so as to effect an improved mixing.

However energy of the magnetic field can be utilized efficiently only with a rather small gap between the magnetic system and the material being mixed. This is achieved by using the baffle plates partially overlapping the drum cavity in a cross-section and made in the form of ferro-magnetic cores, which serve for transmitting the magnetic field pulses, generated by the magnetic system, into the drum interior. The magnetic system in conjunction with ferro-magnetic cores ensures a positive and rapid motion of the ferro-magnetic components of the particle mixture toward the magnetic system, i'.e., in a direction perpendicular to the direction of motion of the material stream within the drum. In addition the ferro-magnetic particles tend to entrain the non-magnetic particles with the ensuing redistribution of the components, As a result the ferro-magnetic material layer is partially disposed above the nonmagnetic one. The revolving drum made in the form of a polyhedral truncated pyramid results in redistribution of the material layers and their transfer longitudinally of the drum.

Further, exposure to the magnetic field pulses tends to increase unformity of distribution of the of the mixture components.

Homogeneity of the mixture resulting from uniform re-distribution of ferro-magne tic and non-magnetic components is achieved by repeated exposure of the ferro-magnetic components of the materials, being mixed, to the action of the magnetic field. Accordingly it would be expedient to dispose the magnetic system made up of separate electromagnets along the drum having ferro-magnetic cores set up on longitudinal edges of the pyramid along a helical line so that when the pyramid revolves they will be alternately located under appropriate electromagnets of the magnetic system. I

With the magnetic system encompassing the upper portion of the drum and containing electromagnets arranged in separate rows and situated along the drum generatrices it 'would'be expedient to mount the ferromagnetic cores on the, longitudinal edges of the pyramid along a helix in such a manner that when the pyramid revolves all cores located in the upper portion of the drum will be simultaneously set up under appropriate electromagnets of the magnetic system.

In order to reduce a gap between the ferro-magnetic core and a corresponding electromagnet of the magnetic system it would be sound practice to use a ferromagnetic unit fastened to the drum exterior above each ferro-magnetic core which is a'core extension.

Thus, the device proposed herewith for continuous mixing of powdered materials ensures, along with high production rate, high quality of mixtures, whereas a high intensity of the mixing process makes it possible to perform it continuously.

BRIEF DESCRIPTION OF THE DRAWINGS To make the essence of the present invention more fully apparent given below is the description of exemplary embodiments of the proposed device for mixing continuously powdered materials; the description refers to the appended drawings, wherein:

FIG. 1 is a principal layout of the device for the continuous mixing of powdered materials (a longitudinal cross-sectional view), conforming to the invention;

FIG. 2 is a cross-section lI-II OF FIG. 1;

FIG. 3 depicts a modified version of the exemplary embodiment, conforming to the invention;

FIG. 4 is a cross-section IV-IV of FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT A device for the continuous mixing of powdered materials comprises revolving drum 1 in the form ofa polyhedral truncated pyramid (trihedral, as shown in FIGS. 1 and 2, and hexahedral as given in FIGS. 3 and 4) resting on tires 2 and 3 (FIGS. 1 and 3).

Longitudinal axis -0 of drum 1 is inclined to a horizontal plane to ensure movement of the materials being mixed, lengthwise drum 1.

Powdered materials 4 to be mixed are charged through hopper 5 located on the side of smaller base 6 of the pyramid, while discharging of the mixed powder material occurs through feed hopper 7 disposed on the side of larger base 8 of the pyramid.

Rotation of drum 1 is by means of an electric drive (not shown in FIGS. 1, 2, 3 and 4 through gear train 9.

On the exterior and fixedly mounted above drum 1 is magnetic system 10 (FIGS. 1 and 4) generating a pulse magnetic field. Enclosed in drum 1 are baffle plates fastened with the aid of rigid points, the baffle plates being made in the form of ferro-magnetic cores 11 being displaced in relation to each other and overlapping partially the cross-section of the cavity of drum 1 (as given in FIGS. 2 and 4).

Ferro-magnetic cores 11 in conjunction with magnetic system 10, generating the pulse magnetic field, except a positive force on ferro-magnetic components of powdered materials 4 and cause the materials to move repeatedly in a direction at right angles to the direction of motion of the material flow in the drum.

The nature of action exerted by the magnetic field upon the ferro-magnetic component is determined by the arrangement of electromagnets in the form of solenoids 12, of which the magnetic system is composed, relative to the drum.

Preferably, the magnetic system 10 may be in the form of solenoids 12 (FIGS. 1 and 2) stationarily mounted in a single row parallel to the generatrix of drum 1. In that case ferro-magnetic cores 11 are secured on lengthwise edges 13 of drum 1 along a helix so that when drum 1 is revolved each of them is disposed altcrnately under appropriate electromagnets in the form of solenoids 12 of the magnetic system.

The latter may encompass the upper portion of drum 1, as shown in FIG. 4. If that is the case, it consists of separate rows 14 of electromagnets in the form of solenoids 12 located parallel to the generatrices of drum 1 (FIG. 3) with ferro-magnetic cores 1] being fastened on longitudinal edges 13 of drum 1 along a helical line in such a manner that when the drum rotates all cores 11 disposed in its upper portionare synchronously located under appropriate electromagnets of magnetic system 10.

For reducing a gap between magnetic system 10 and ferro-magnetic cores 11, securingly attached to the exterior of the drum 1 above each core 11 is a ferromagnetic unit 15 (FIGS. 2 and 4) which is so disposed as to be aligned with the core 11.

The proposed device for the continuous mixing of powdered materials operates as follows:

Both ferro-magnetic and non-magnetic components of material 4 (FIGS. 1 and 3) are continuously fed in the form of separate streams through a hopper 5 into a revolving drum 1. When drum 1 rotates, material 4 is interspersed while moving towards hopper 7. Simultaneously, magnetic system 10 operates for generating a pulse magnetic field of a certain frequency which is transferred into drum 1 through ferro-magnetic units 15 and ferromagnetic cores 11.

If magnetic system 10 is made as electromagnets in the form of solenoids 12 arranged in a single row along the generatrix of drum 1 (FIGS. 1 and 2), cores 11, located along the helix, are alternately located under appropriate electromagnets which are in the form of solenoids 12. As drum 1 revolves and the first (from the charging side) ferro-magnetic core 11 together with ferro-magnetic unit 15 approaches a region under electromagnets in the form of the solenoids 12 of magnetic system 10, the magnetic field pulses will be transferred through the core into the drum 1 and under the action of the field the particles of the ferro-magnetic component in the material 4 will move abruptly toward the ferro-magnetic core, entraining non-magnetic particles. This results in a partial re-distribution of the components. In the meantime on completion of the pulse action of the magnetic system the layer of the ferromagnetic component will be disposed above the nonmagnetic one.

Further rotation of drum 1 leads, on account of the drum shape, to an abrupt collapse of the material with the magnetic layer being transferred under the nonmagnetic. Cores 11 being disposed along the helical lines, either of the cores approaching alternately its place under the appropriate electromagnet, delivers the magnetic field pulses again and the process of mixing of the material being transferred is repeated.

If magnetic system 10 encompasses the upper portion of drum 1 (FIGS. 3 and 4) and consists of separate rows 14 of electromagnets in the form of solenoids 12, located along the generatrices of drum 1, core 11, set up along a helical line, will be simultaneously disposed under appropriate electromagnets 12 of the magnetic system. As all cores 1] in the upper portion of drum 1 will move under appropriate electromagnets 12, they serve for transmitting the magnetic field pulses into drum 1. Under the action of the magnetic field the particles of the ferro-magnetic component will move suddenly towards either of cores ll entraining nonmagnetic particles.

As in the upper portion of drum 1 ends of cores 11 are arranged in different planes, the ferro-magnetic particles move along drum 1 at one and the same time but in various directions, which tends to increase the number of collisions between these particles.

.This leads to partial re-distribution of the compo nents. Meanwhile as soon as the pulse action of the magnetic system is completed, the layers of the ferromagnetic component will rise to regions above those of the non-magnetic material.

On revolving further, drum 1 causes, due to its shape, an abrupt collapse of the material through which the magnetic layer will be located under the non-magnetic.

Next the magnetic field pulses will act again upon the material and the process of transfer of material 4 is re peated.

Thus one and the same volume element of material 4 is exposed to the action of the magnetic field over and over again which results in uniform continuous mixing of the components.

At the moment when ferro-magnetic cores 11 move away from the magnetic system, the magnetic field is not transferred through them and-they act as baffle plates contributing to additional stirring of material 4 moving along drum 1.

What is claimed is:

l. A device for continuous mixing of powdered materials having ferromagnetic components therein, comprising: a drum mounted for rotation on its own longitudinal axis and made in the form of a polyhedral truncated pyramid which is fed atone end thereof with powdered materials to be mixed which after mixing get discharged at the other end; a means for rotating said drum on said longitudinal axis; a means for charging the powdered materials at said one end; a means for discharging the mixed materials at said other end; baffle plates made of ferromagnetic material and fastened rigidly to an inner side of the drum and overlapping partially the drum cavity in cross section; and a stationary magnetic system means mounted adjacent to and outside of the drum for generating a pulse magnetic field which is conveyed into thedrum cavity through the ferromagnetic baffle plates to reach the powdered materials, so as to improve the mixing of said ferromagnetic components in the powdered materials with the rest of the powdered materials.

2. A device of claim 1, in which the said magnetic system is disposed substantially parallel to a generatrix of the said drum and is made up of separate electromagnets.

3. A device of claim 2, in which the said baffle plates are located on the edges of the said pyramid along a helical line so that when the pyramid is revolved they are alternately disposed under appropriate electromagnets of the magnetic system.

4. A device of claim 1, in which the axis of the drum is somewhat inclined to the horizontal and said magnetic system encompasses an upper portion of the said drum and consists of separate rows of the electromagnets disposed along generatrices of the drum.

5. A device of claim 4, in which the baffle plates of ferromagnetic material are mounted on the edges of the said pyramid along the helical line so that when the pyramid is revolved all the cores located in an upper portion of the drum are simultaneously placed under appropriate electromagnets of the magentic system.

6. A device of claim 1, in which rigidly fastened to the exterior of the said drum and aligned with each said baffle plate is a ferro-magnetic member which forms a magnetic extension of the corresponding baffle plate of electromagnetic material. 

1. A device for continuous mixing of powdered materials having ferromagnetic components therein, comprising: a drum mounted for rotation on its own longitudinal axis and made in the form of a polyhedral truncated pyramid which is fed at one end thereof with powdered materials to be mixed which after mixing get discharged at the other end; a means for rotating said drum on said longitudinal axis; a means for charging the powdered materials at said one end; a means for discharging the mixed materials at said other end; baffle plates made of ferromagnetic material and fastened rigidly to an inner side of the drum and overlapping partially the drum cavity in cross section; and a stationary magnetic system means mounted adjacent to and outside of the drum for generating a pulse magnetic field which is conveyed into the drum cavity through the ferromagnetic baffle plates to reach the powdered materials, so as to improve the mixing of said ferromagnetic components in the powdered materials with the rest of the powdered materials.
 2. A device of claim 1, in which the said magnetic system is disposed substantially parallel to a generatrix of the said drum and is made up of separate electromagnets.
 3. A device of claim 2, in which the said baffle plates are located on the edges of the said pyramid along a helical line so that when the pyramid is revolved they are alternately disposed under appropriate electromagnets of the magnetic system.
 4. A device of claim 1, in which the axis of the drum is somewhat inclined to the horizontal and said magnetic system encompasses an upper portion of the said drum and consists of separate rows of the electromagnets disposed along generatrices of the drum.
 5. A device of claim 4, in which the baffle plates of ferromagnetic material are mounted on the edges of the said pyramid along the helical line so that when the pyramid is revolved all the cores located in an upper portion of the drum are simultaneously placed under appropriate electromagnets of the magentic system.
 6. A device of claim 1, in which rigidly fastened to the exterior of the said drum and aligned with each said baffle plate is a ferro-magnetic member which forms a magnetic extension of the corresponding baffle plate of electromagnetic material. 